In my experience, you take a kid fishing rather than fish with a kid. He'll do the fishing, you'll do the untangling, unhooking, knot tying, etc. But I've never gone out with a kid and not had at least as much fun helping them catch fish as I would have had catching them myself!! Good luck and get 'em hooked while they're young, before the video games and television gets 'em!
Best advise of all right there. I have 4 and that is how they all learned. The first time we took our oldest, my wife asked, "where's your rod"? After that trip, she left hers at home on the next one. It can be a busy time on the water, but well worth it.